Turkey says it is planning for military intervention in Syria’s Kurdish-controlled Afrin and Manbij regions in response to a “threat” posed by U.S.-backed Kurdish militia fighters.

Turkish Foreign Minister Mevlut Cavusoglu said on January 18 that Ankara continues to “mistrust” the United States over its support for Syrian Kurdish forces along Turkey’s southern border.

Cavusoglu also said Russia should not oppose operations in Syria’s Afrin region and that Ankara would coordinate with Moscow and Tehran on air operations there.

Cavusoglu made the remarks a day after U.S. Secretary of State Rex Tillerson said he met with the Turkish foreign minister to clarify the issue of U.S. support for Syrian Kurdish fighters.

Turkey’s state-run Anadolu news agency reported on January 18 that Turkish security forces have been ordered to prepare for intervention into Syria’s Kurdish-held regions of Afrin and Manbij.

The report said a Turkish military buildup along the border was continuing with tanks arriving on January 18 in Turkey's Eastern Mediterranean coastal province of Hatay in response to “a border security threat.”

Anadolu also said a National Security Council meeting headed by Turkish President Recep Tayyip Erdogan late on January 17 concluded that Turkey should take “immediate” and “resolute” steps to protect itself from threats emanating out of western Syria.

On January 15, Erdogan threatened to crush an "army of terror" he claims the United States is trying to set up on Turkey’s border with Syria.

Ankara is angry that Washington is allied with Kurdish People's Protection Units (YPG) that have been fighting against Islamic State militants in Syria. Turkey considers the YPG to be a terrorist organization.

Turkey’s government was infuriated by a January 14 statement from the U.S.-led coalition in Syria that said Washington would help set up a new 30,000-strong border force in Syria that includes the YPG.

Tillerson says he told Cavusoglu on January 17 that the "entire situation has been misportrayed” and “misdescribed” by “some people” who “misspoke."

He said the United States aims to provide training to local elements in Syria -- not create a new border security force.

But Cavusoglu said on January 18 that Ankara was “not completely satisfied” by Tillerson’s explanation, adding that Turkey’s “mistrust” of Washington continues.

Cavusoglu said Ankara wants to see “concrete steps” from the United States on ending cooperation with “terrorist groups.”